Relative Acceleration Noise Mitigation for Nanocrystal Matter-wave Interferometry: Application to Entangling Masses via Quantum Gravity

TL;DR

This paper proposes a method to mitigate relative acceleration noise in matter wave interferometry by using a freely falling setup, enabling tests of quantum gravity with entangled masses.

Contribution

It introduces a noise mitigation strategy that does not require active acceleration tracking, enhancing the feasibility of quantum gravity experiments with matter wave interferometers.

Findings

Inertial noise can be reduced below critical levels with pressure and temperature control.

Gravity-gradient noise can be fully mitigated in a controlled environment.

Entanglement-based tests of quantum gravity are feasible with the proposed noise mitigation.

Abstract

Matter wave interferometers with large momentum transfers, irrespective of specific implementations, will face a universal dephasing due to relative accelerations between the interferometric mass and the associated apparatus. Here we propose a solution that works even without actively tracking the relative accelerations: putting both the interfering mass and its associated apparatus in a freely falling capsule, so that the strongest inertial noise components vanish due to the equivalence principle. In this setting, we investigate two of the most important remaining noise sources: (a) the non-inertial jitter of the experimental setup and (b) the gravity-gradient noise. We show that the former can be reduced below desired values by appropriate pressures and temperatures, while the latter can be fully mitigated in a controlled environment. We finally apply the analysis to a recent proposal for testing the quantum nature of gravity [S. Bose et. al. Phys. Rev. Lett 119, 240401 (2017)] through the entanglement of two masses undergoing interferometry. We show that the relevant entanglement witnessing is feasible with achievable levels of relative acceleration noise.